JPH0220128A - Multichannel radio communication system - Google Patents

Abstract

PURPOSE: To attain a multiple channel operation by providing plural transmitters/receivers and plural radio equipment in at least the same number as the necessary number of channels, and allowing each radio equipment to include an antenna, signal transmitter, signal receiver, and voice signal processor. CONSTITUTION: 6 RF link antennas are vertically laminated from A1 to A6. Each radio equipment BU1-BU6 is mounted in each antenna, and residual devices, for example, devices which do not have any close relation with the RF circuits such as a central processor and an exchange line are housed in a common controller WL set at the foot of the antenna array. The common controller WL generates burst synchronization and TDM timing signals to each radio equipment BU1-BU6. This system is a main device, and a cordless transmitter/receiver positioned at a remote place is used. The antenna suitable for a basic device and a transmitter/receiver 1 is a di-pole constituted of two primary parts 2 and 3, and constituted of an electric circuit substrate, and a signal transmitter, signal receiver, and voice signal processor are mounted in the substrate, and they are shown as parts 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multi-channel wireless communication system.

The system has an application in the field of cordless telephones, where a plurality of handsets communicate with respective radio modules provided in a common control unit.

BACKGROUND OF THE INVENTION Several problems must be overcome when connecting multiple radio links within one common control device (constituting a common antenna feed line). These include problems with antenna coupling systems, receiver desensitization, and transmitter intermodulation.

Antenna coupling system When connecting multiple wireless devices (transmitter and receiver) within one common control device, connect the output of the wireless system to a common feed line by connecting the outputs of the wireless devices. Therefore, a common antenna feeding system must be created. The low-loss techniques currently used to connect multiple wireless systems to a single common feed line are narrowband techniques in nature and are not applicable to multichannel wideband systems such as cordless telephones.

However, broadband coupling techniques are possible even in these operating frequency bands, but with losses (integer multiples of 3 dB). This loss degrades the overall system performance in terms of system receive sensitivity and transmit power, necessitating the use of a 1-linear, low noise preamplifier and power amplifier.

Decreased receiver sensitivity - A stationary transmitter interferes with the receiver's input, reducing the receiver's sensitivity and reducing the signal-to-noise ratio.

Transmitter Intermodulation The multiple transmitter outputs combine to produce an intermodulation product. This is fed back to the output stage of each power amplifier, creating intermodulation products in and out of band due to the "nonlinearity" of the output stage (depending on the frequency spacing of each transmitter). This causes an empty channel to appear as if it were in use.

SUMMARY OF THE INVENTION Current cordless telephone systems operate with a 5QMII+ or less wireless link between the base unit and the handset, and are capable of retracting the antenna. However, the system of the present invention operates in the frequency range 864-868M1b.

The advantages of the system of the present invention are that it is capable of multi-channel operation, that each handset can be equipped with a built-in antenna instead of a retractable antenna, and that multiple antennas can be stacked on a common control unit. This is something that can be done.

It is an object of the present invention to provide a multi-channel wireless communication system having the above-mentioned advantages and thereby being freed from the limitations of known systems.

According to the invention, the invention comprises a plurality of handsets and a plurality of radio devices, at least as many as the number of channels required, each radio device including an antenna, a signal transmitter, a signal receiver and an audio signal processor; A multi-channel wireless communication system for cordless telephone communication is provided.

Also in accordance with one aspect of the invention, the signal transmitter, signal receiver, and audio signal processor of each wireless device are housed within a space created by an associated antenna, and the antenna is comprised of two main parts; phase r7. They are far apart and form a dipole.

According to another aspect of the invention, a plurality of antennas are stacked vertically with a common control device, and the common control device is located at the bottom of them.

According to yet another aspect of the invention, an antenna is provided within each handset.

(Examples) Examples of the present invention will be described below with reference to the drawings.

Several radio devices +31,82BN are shown in FIG. 1, each with an antenna Δ1. A2. A
It has an N. These devices are equipped with a central control bus CCB and an ADPCM (adaptive delta pulse code modulation) audio bus S.
It is connected to B. The central control bus CCB also includes a switched line interface circuit ELIC and a timing generator T.
G, as well as input/output expansion, bus interface and latch circuit 10/IF. audio bus SB
is connected to the timing generator TG and the analog/ADPCM interface circuit AAI. The microprocessor MP that controls these is connected to the circuit 10/■I? via the highway bus HB. It is connected to the. The program memory PROG and random access memory RAM are also bus HI.
Connected to 3. The microprocessor MP is equipped with a reset and monitoring device RW, and the random access memory RAM is equipped with a backup battery BAT to preserve the contents of the memory in the event of a power failure.

This system is the main device and uses a remote cordless handset. A call is initiated and the switched line is captured by pressing the appropriate button on the button device, such as 2x, 3x, etc. for an internal call, or 1.2 or 3 for an external call. The handset emits an audible tone to indicate that it has been called.

Conversion between analog voice signals and ADPCM g-voice signals takes place in the code handset and switched line circuits.

The common control unit is controlled by a microprocessor.

Distributed microprocessors are 864-868
MII! RF link radio equipment operating in the frequency range of The internal and external routing of audio and control signals within the common control unit is carried by a TD carrying digitally encoded signals.
This is done on an M (time division multiplex) bus. Voice and control signals passing over the RF link are also encoded in digital form.

The switched line is monitored by a high impedance (>10 Mohm) detector.

FIG. 2 schematically shows the arrangement of the common control device and antenna assembly. In this arrangement, six RF link antennas are stacked vertically with At-A6. Each wireless device Bu
A t-BU6 is mounted in each antenna, and the antennas are stacked vertically. The remaining equipment, such as the central processor, switched line circuitry, etc. that are not closely related to the RF circuitry, are housed in a common control unit WL located at the foot of the antenna array.

The common controller WL generates burst synchronization and TDM timing signals to each wireless unit BUI-BU6. It is also connected to the telephone line that is connected to the exchange.

All transmitters and receivers are synchronized within a common control unit and any additional radio links added to the base unit are slaved with the first base unit maintaining system control. All wireless devices and antennas receive together and transmit together in time division multiplex mode, or burst mode. The transmission therefore takes place in digital form.

Regarding transmitter intermodulation, the maximum signal coming out of each transmitter is typically +5 dBm. This is fed back to the transmitter placed along with the signal. With a +35 dBm power amplifier output device, the third-order disturbance is -63 dB.
+n intermodulation products. At least another 35 dBm of attenuation would be required to bring the intermodulation products to a level below the required "free channel acquisition threshold."

However, by inserting an isolator (in the circulation circuit) before the input of each stage, 864MI+! With approximately 35 dB of isolation at , the intermodulation specification of the output device would be reduced to O dB. This is the level required of the handset when the maximum input signal is -30 dB.

By carefully setting the placement of the asteners and the amount of separation between the transmitter output stages, it is possible to uniformly and closely arrange the radio devices forming the "radiating panel", allowing expansion of the basic device as a unit. It becomes possible to do so.

Designing an antenna suitable for the handset and basic equipment requires the inclusion of one radio module within the dipole. The wireless module includes a microprocessor, voice processor, etc. With such a basic design, it would be possible to extend this configuration method to cascade N wireless devices, which would create a very wideband dipole.

FIG. 3 shows the basic device and/or an antenna suitable for the handset 1. In FIG. The antenna is a gouball consisting of two main parts 2.3. The dial antenna 23, which is separated from the first part 2 and the second part 3, is composed of an electric circuit board, and a signal transmitter, a signal receiver, and an audio signal processor are mounted in the board. , these are shown as part 4.

The antenna acts to shield nearby electrical circuits and prevent RFT interference.

An alternative configuration is shown in FIG. 3a, in which the third part 3 is narrower than the second part 2<t-' C1 the third part 3 is placed inside the second part 2 L2-( The image parts 3 and 2J- are separated by 1-.

The following examples 1- limit the scope of the present invention (+4
〔　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　a different way of realizing the present invention or extension tH';

Figure i7) Explanation of part Figure 1 shows the central control unit y'11 which controls the radio equipment. FIG. 2 shows the layout of the common control unit and the A-17-S5-B. Figure 3 3L ゛3・1 [η
Receiver anti-1-+7) Shape diagram G "7"1-.

To the telephone exchange ii) Shinoji Porridge figure Figure 3a

Claims (7)

[Claims] (1) comprising a plurality of handsets and a plurality of radio devices, at least as many as the number of channels required, each radio device including an antenna, a signal transmitter, a signal receiver, and an audio signal processor; A multichannel wireless communication system for cordless telephone communications. (2) The apparatus of claim 1, wherein the signal transmitter, signal receiver, and audio signal processor of each wireless device are housed within a space created by an associated antenna, and the antenna is comprised of two main parts, each of which is interconnected. A multi-channel wireless communication system characterized by forming dipoles apart. (3) The device according to claim 2, wherein the antenna is composed of two main parts, one part being wrapped inside the other part and separated from each other to form a dipole. A multi-channel wireless communication system. (4) The apparatus according to claim 2, characterized in that the plurality of antennas are vertically stacked together with a common control device, the common control device being installed at the bottom thereof. system. (5) In the device according to claim 1, 2, 3 or 4,
A multi-channel radio communication system, characterized in that each handset is provided with a dipole antenna inside it. 6. The multichannel wireless communication system of claim 5, wherein the signal transmitter and signal receiver are synchronized with a common control unit. (7) In the device according to claim 6, the channel is 864.
A multi-channel wireless communication system, characterized in that it operates at ~868 MHz.